Corrosion Inhibition of C38 Steel in 1 M HCl: A Comparative Study of Black Pepper Extract and Its Isolated Piperine

Abstract

Corrosion inhibition effect of black pepper (BP) extract and its piperine isolated from BP on corrosion of C38 steel in 1 M HCl solution was investigated by weight loss method. Piperine was isolated by ethanol in yield 6 from ground BP. Results obtained from weight loss measurements indicate that the natural compounds tested exhibit higher efficiency exceeding 95% at 2g/L. The presence of piperine decreases hugely the corrosion rate and its inhibition efficiency (E%) increases with concentration to attain 99 % at 10-3M. Piperine adsorbs on the steel surface according Langmuir isotherm. Adsorption enthalpy were determined and discussed. Effect of temperature was also investigated and activation parameters were evaluated